1. Field of the Invention The invention relates to an inductive component having a strip-wound core which is wound from an amorphous ferromagnetic alloy, as well as to a production method for strip-wound core strips composed of amorphous ferromagnetic material.
2. Description of the Prior Art
In order to achieve good soft-magnetic characteristics, amorphous ferromagnetic alloys which are virtually free of magnetostriction must also be subjected to heat treatment. Typically, they are in this case tempered in a magnetic field in order to deliberately achieve a flat B-H loop.
The latter is carried out according to the prior art on ready-wound strip-wound cores since, as a rule, the amorphous material becomes brittle during tempering and the reduction in internal mechanical stresses required for maximum permeabilities can be achieved, these stresses being a result of production and also being caused by the winding of the strip-wound core.
One possibility for producing amorphous ferromagnetic strip-wound core strips which have been heat treated in a magnetic field is stationary heat treatment of the strip-wound core strips, which have been wound into coils for delivery, in so-called transverse-field furnaces. However, this method is highly critical with regard to good reproducibility. Since large amounts of material are involved, relatively long treatment times of several hours, and up to days in the worst case, must be carried out in order to ensure that the coils for delivery are uniformly heated through. Owing to the long treatment times, it is in this case necessary to operate at relatively low temperatures in the region of about 200.degree. C..ltoreq.T.ltoreq.250.degree. C., in order to preclude thermal embrittlement of the material. However, this means that the variability range of the magnetic characteristics that can be achieved is very greatly limited, particularly with regard to the achievable permeabilities.
German Patentschrift 33 24 729 discloses a method for production of an amorphous magnetic alloy having a high permeability, in which a strip composed of an amorphous magnetic cobalt/basic alloy, which has a material proportion of iron of 5%, is produced by means of rapid solidification, and in which the amorphous magnetic strip is subjected to a magnetic field transversely with respect to the strip direction as it passes through heat treatment.